{"observation":{"id":"423601f9-0ef6-48b2-8f30-ecbcf9624efe","tool":"kling-ai","tool_name":"Kling AI","criterion":"sync-accuracy","criterion_name":"Sync Accuracy","criterion_definition":"The effect is timed to the specific action or object rather than playing generically across the whole clip.","criterion_evidence_type":"transformation","criterion_rank_role":"decisive","criterion_rank_role_reason":"Timing the effect to the exact action is essential to believable automated sound design. (3 of 3 judges)","scenario":"bird-nature-video","scenario_name":"Bird/Nature Video","group_tag":"auto-sfx-video-generation","scenario_description":"A video featuring a bird in frame, used to test whether generated chirping or ambient sounds sync to the specific animal and movement shown on screen.","modality":"video","input_text":null,"input_artifact_refs":[],"stresses":["sync accuracy to a visible subject","nature/animal sound matching","avoiding generic ambience that ignores timing","scene-specific audio generation"],"verdict":"failed","score":null,"score_total":null,"note":"The subject-specific sound can fail to line up with the object’s on-screen behavior.","evidence_state":"verified","source":null,"artifacts":[{"url":"https://d3epheqghktydj.cloudfront.net/research-media-bird-88b167f7f533.mp4","role":"input","alt":"Bird.mp4"},{"url":"https://d3epheqghktydj.cloudfront.net/kling-ai-kling-ai-bird-chirping-output-1-f90f2a2a825f.mp4","role":"output","alt":null},{"url":"https://d3epheqghktydj.cloudfront.net/kling-ai-kling-ai-bird-chirping-output-2-afa2b7a2a1cb.mp4","role":"output","alt":null},{"url":"https://d3epheqghktydj.cloudfront.net/kling-ai-kling-ai-bird-chirping-output-3-4cb15eb669f1.mp4","role":"output","alt":null},{"url":"https://d3epheqghktydj.cloudfront.net/kling-ai-kling-ai-bird-chirping-output-4-561115c82942.mp4","role":"output","alt":null}],"run_id":"90451942-9055-4e8c-85e6-17c773437ed7","study_title":"Automatically Add Relevant Sound Effects to Videos","study_kind":"generation","research_task":"86b84w3x5","tested_at":null,"completeness":"input-and-output","input":{"state":"not-captured","text":null,"files":[],"modality":"video","stresses":["sync accuracy to a visible subject","nature/animal sound matching","avoiding generic ambience that ignores timing","scene-specific audio generation"]},"tool_page_slug":"kling-ai","tool_url":"https://aidemos.com/tools/kling-ai","permalink":"https://aidemos.com/evidence/423601f9-0ef6-48b2-8f30-ecbcf9624efe","api_url":"https://ai.aidemos.com/v1/observations/423601f9-0ef6-48b2-8f30-ecbcf9624efe"},"peers":[{"id":"ea14f7df-bcae-4c53-af53-bc37821e7b99","tool":"descript","tool_name":"Descript","verdict":"failed","score":null,"score_total":null,"note":"On the bird test, the tool failed to sync sound to the animal's actual behavior, playing bird chirping continuously for the full 10-second clip even though the bird chirped only 2–3 times.","artifact_count":1,"thumbnail":"https://d3epheqghktydj.cloudfront.net/descript-descript-bird-chirping-output-1-010b2e8aa8d8.mp4","evidence_url":"https://aidemos.com/evidence/ea14f7df-bcae-4c53-af53-bc37821e7b99"},{"id":"3c325f18-9f10-480d-b154-f10498f7f11a","tool":"fine-voice","tool_name":"Fine Voice","verdict":"struggled","score":60.0,"score_total":100.0,"note":"Even with prompt guidance, chirps did not line up with the bird's actual chirping moments; the better bird output was only about 60% satisfying.","artifact_count":4,"thumbnail":"https://d3epheqghktydj.cloudfront.net/research-media-bird-88b167f7f533.mp4","evidence_url":"https://aidemos.com/evidence/3c325f18-9f10-480d-b154-f10498f7f11a"},{"id":"2936e1bf-5a08-4140-8e22-568ab1ab9bae","tool":"flexclip","tool_name":"FlexClip","verdict":"failed","score":null,"score_total":null,"note":"The chirping was not tied to the bird on screen; it played generically instead of syncing to the visible animal's action.","artifact_count":2,"thumbnail":"https://d3epheqghktydj.cloudfront.net/research-media-bird-88b167f7f533.mp4","evidence_url":"https://aidemos.com/evidence/2936e1bf-5a08-4140-8e22-568ab1ab9bae"},{"id":"8edf5ecc-9e2f-40ad-98a9-b81a4dd468bf","tool":"mirelo","tool_name":"Mirelo","verdict":"worked","score":null,"score_total":null,"note":"It can achieve near-perfect timing on natural footage; one variant was reported as so accurately synced that the sound effects seemed like part of the video.","artifact_count":2,"thumbnail":"https://d3epheqghktydj.cloudfront.net/research-media-bird-88b167f7f533.mp4","evidence_url":"https://aidemos.com/evidence/8edf5ecc-9e2f-40ad-98a9-b81a4dd468bf"}],"other_criteria":[{"id":"75407f0b-f13b-4e88-8bc3-8e84da3296a2","criterion":"audio-quality","criterion_name":"Audio Quality","rank_role":"decisive","verdict":"worked","score":null,"score_total":null,"note":"Prompt assistance can make the output audible and improve volume over the no-prompt baseline.","artifact_count":5,"evidence_url":"https://aidemos.com/evidence/75407f0b-f13b-4e88-8bc3-8e84da3296a2"},{"id":"e928b323-df69-4f9f-9042-9d72294d89f2","criterion":"scene-sound-relevance","criterion_name":"Scene-Sound Relevance","rank_role":"decisive","verdict":"struggled","score":null,"score_total":null,"note":"The tool can omit the featured subject’s specific sound at the moment it appears and fall back to generic ambience.","artifact_count":5,"evidence_url":"https://aidemos.com/evidence/e928b323-df69-4f9f-9042-9d72294d89f2"},{"id":"155aa78a-cdb6-47d7-bec1-215e9b885c2b","criterion":"variant-usefulness","criterion_name":"Variant Usefulness","rank_role":"context","verdict":"mixed","score":null,"score_total":null,"note":"The fourth variant can be only marginally better than the others, so the extra variants provide limited benefit.","artifact_count":5,"evidence_url":"https://aidemos.com/evidence/155aa78a-cdb6-47d7-bec1-215e9b885c2b"}],"appears_in":[{"page_type":"ranking","slug":"ai-sound-effect-generators","title":"Best AI Tools to Automatically Add Sound Effects to Videos","url":"https://aidemos.com/best/ai-sound-effect-generators","binding":"run"},{"page_type":"tool","slug":"fine-voice","title":null,"url":"https://aidemos.com/tools/fine-voice","binding":"run"},{"page_type":"tool","slug":"flexclip","title":null,"url":"https://aidemos.com/tools/flexclip","binding":"run"},{"page_type":"tool","slug":"kling-ai","title":null,"url":"https://aidemos.com/tools/kling-ai","binding":"run"},{"page_type":"tool","slug":"mirelo","title":null,"url":"https://aidemos.com/tools/mirelo","binding":"run"}],"same_scenario":[{"id":"ea14f7df-bcae-4c53-af53-bc37821e7b99","tool":"descript","tool_name":"Descript","verdict":"failed","score":null,"score_total":null,"note":"On the bird test, the tool failed to sync sound to the animal's actual behavior, playing bird chirping continuously for the full 10-second clip even though the bird chirped only 2–3 times."},{"id":"3c325f18-9f10-480d-b154-f10498f7f11a","tool":"fine-voice","tool_name":"Fine Voice","verdict":"struggled","score":60.0,"score_total":100.0,"note":"Even with prompt guidance, chirps did not line up with the bird's actual chirping moments; the better bird output was only about 60% satisfying."},{"id":"2936e1bf-5a08-4140-8e22-568ab1ab9bae","tool":"flexclip","tool_name":"FlexClip","verdict":"failed","score":null,"score_total":null,"note":"The chirping was not tied to the bird on screen; it played generically instead of syncing to the visible animal's action."},{"id":"8edf5ecc-9e2f-40ad-98a9-b81a4dd468bf","tool":"mirelo","tool_name":"Mirelo","verdict":"worked","score":null,"score_total":null,"note":"It can achieve near-perfect timing on natural footage; one variant was reported as so accurately synced that the sound effects seemed like part of the video."}]}